From ab34a1de511b026eddd8021a6a9dab8d831542fc Mon Sep 17 00:00:00 2001
From: Paul Gardner-Stephen <paul@servalproject.org>
Date: Sat, 20 Apr 2019 23:04:50 +0930
Subject: [PATCH] implement bucky keys in keyboard scan routine

---
 c64/kernal/keyboard_matrix.s | 66 +++++++++++++++++++++++++++++++-----
 c64/kernal/scan_keyboard.s   |  6 ++++
 2 files changed, 64 insertions(+), 8 deletions(-)

diff --git a/c64/kernal/keyboard_matrix.s b/c64/kernal/keyboard_matrix.s
index c37c710f..e5b29e5c 100644
--- a/c64/kernal/keyboard_matrix.s
+++ b/c64/kernal/keyboard_matrix.s
@@ -7,17 +7,67 @@ keyboard_matrixes:
 	;; Unshifted matrix built by refering to
 	;; Compute's Mapping the 64 p38-39
 	;; and C64 PRG pages 379-381
-	.byte 20,13,29,136,133,134,15,17
+	.byte 20,13,$1D,136,133,134,135,17
 	.byte $33,87,$41,$34,90,83,$45,$00
 	.byte $35,$52,$44,$36,$43,$46,$54,88
-	.byte $37,89,$47,$38,$42,$48,$55,$56
+	.byte $37,$59,$47,$38,$42,$48,$55,$56
 	.byte $39,$49,$4A,$30,$4D,$4B,$4F,$4E
-	.byte 43,$50,$4C,45,46,58,$40,44
-	.byte $23,42,59,$13,$00,61,94,47
-	.byte $31,95,$00,$32,$20,$00,$51,3
+	.byte $2B,$50,$4C,45,46,58,$40,44
+	.byte $5C,$2A,59,$13,$00,$3D,94,$2F
+	.byte $31,$5F,$00,$32,$20,$00,$51,3
 
-	;; XXX - Implement shifted
+	;; Shifted keyboard
+	;; Values computed by running a program like:
+	;; 10 GETA$:IFA$=""GOTO10
+	;; 20 ?ASC(A$):GOTO10
+	;; and converting the values 
+	.byte $94,$8D,$9D,$8C,$89,$8A,$8B,$91
+	.byte $23,$77,$61,$24,$7A,$73,$65,$00
+	.byte $25,$72,$64,$26,$63,$66,$74,$78
+	.byte $27,$79,$67,$28,$62,$68,$75,$76
+	.byte $12,$69,$6A,$92,$6D,$6B,$6F,$6E
+	.byte $DB,$70,$6C,$DD,43E,$5B,$BA,$3C
+	.byte $A9,$C0,$5D,$93,$00,$3D,$DE,$3F
+	.byte $21,$5F,$00,$22,$A0,$00,$71,$83
 
-	;; XXX - Implement control modified
+	;; Control modified keyboard
+	.byte $00,$00,$00,$00,$00,$00,$00,$00
+	.byte $1C,$17,$01,$9F,$1A,$13,$05,$00
+	.byte $9C,$12,$04,$1E,$03,$06,$14,$18
+	.byte $1F,$19,$07,$9E,$02,$08,$15,$16
+	.byte $12,$09,$0A,$92,$0D,$0B,$0F,$0E
+	.byte $00,$10,$0C,$00,$00,$1B,$00,$00
+	.byte $1C,$00,$1D,$00,$00,$1F,$1E,$00
+	.byte $90,$06,$00,$05,$00,$00,$11,$00
+
+	;; Vendor key modified keyboard
+	.byte $94,$8D,$9D,$8C,$89,$8A,$8B,$91
+	.byte $96,$B3,$B0,$97,$AD,$AE,$B1,$00
+	.byte $98,$B2,$AC,$99,$BC,$BB,$A3,$BD
+	.byte $9A,$B7,$A5,$9B,$BF,$B4,$B8,$BE
+	.byte $30,$A2,$B5,$30,$A7,$A1,$B9,$AA
+	.byte $A6,$AF,$B6,$DC,$3E,$5B,$A4,$3C
+	.byte $A8,$DF,$5D,$93,$00,$3D,$DE,$3F
+	.byte $81,$5F,$00,$95,$a0,$00,$AB,$83
+
+
+keyboard_matrix_lookup:
+	;; Work out if normal, shifted, control or Vendor
+	;; modified keyboard. 
+	;; Table contains the offsets into keyboard_matrixes
+	;; that should be used for different values of
+	;; the bottom 3 bits of key_bucky_state
+	;; Interaction is simple to work out when playing
+	;; with a C64:
+	;; CONTROL trumps SHIFT or Vendor
+	;; Vendor + SHIFT = DOES NOTHING
+	;; All 3 does CONTROL
+	.byte $00 		; Normal
+	.byte $40		; Shifted
+	.byte $80		; Control
+	.byte $80		; Control + SHIFT
+	.byte $C0		; Vendor
+	.byte $C0 		; Vendor + SHIFT
+	.byte $80		; Vendor+ CTRL
+	.byte $80		; Vendor + CTRL + SHIFT
 
-	;; XXX - Implement C= modified
diff --git a/c64/kernal/scan_keyboard.s b/c64/kernal/scan_keyboard.s
index 7fa2cc00..551c41fb 100644
--- a/c64/kernal/scan_keyboard.s
+++ b/c64/kernal/scan_keyboard.s
@@ -75,7 +75,13 @@ scan_keyboard:
 
 	;; Convert matrix position to key code
 	;; XXX - Add offset of $40, $80 or $C0 if shift, CONTROL or C= are held down
+	pha
+	lda key_bucky_state
+	and #$7
+	tax
+	pla
 	and #$3f
+	ora keyboard_matrix_lookup,x
 	tax
 	lda keyboard_matrixes,x
 	;; But don't insert $00 characters